Sonochemical synthesis of a Mn3O4/MnOOH nanocomposite for electrochemical energy storage

A Mn3O4/MnOOH nanocomposite was synthesized through a sonochemical process and used for supercapacitor applications. The obtained samples were characterized using a transmission electron microscope (TEM), a high-resolution transmission electron microscope (HRTEM), X-ray diffraction (XRD) and selected-area electron diffraction (SAED). The electrochemical performance of the Mn3O4/MnOOH nanocomposite was investigated as supercapacitor electrode material through cyclic voltammetry (CV), galvanostatic charge/discharge (GC/D) and electrochemical impedance spectroscopy (EIS). Results indicated that ultrasonic time strongly influenced the MnOOH contents in the nanocomposite. The Mn3O4/MnOOH nanocomposite electrode of 0.22 MnOOH content provided a high specific capacitance of 307.8 F g(-1) as well as excellent cycling stability (2% decay after 2000 cycles). Furthermore, the symmetric supercapacitor based on Mn3O4/MnOOH nanocomposite has a reasonable energy density of 10.6 W h kg(-1) and a high power density of 7.4 kW kg(-1). The excellent capacitive performance of the Mn3O4/MnOOH nanocomposite is due to synergistic effect between the Mn3O4 and the MnOOH. (C) 2016 Elsevier B.V. All rights reserved.